The first direct observation of gravitational waves captured the merging of 2 black holes which emitted 3.6 septillion yottawatts of power (3.6×10⁴⁶ watts), greater than the combined power of all light radiated by all the stars in the observable universe https://t.co/s1T5uNB2gB https://t.co/ezx8D1wLfm

If you follow the story back to the Wikipedia source he quotes then it says there that the power was 3.6 x 10^49 watts which is actually a thousand times bigger than the number in his brackets. I reckon that would be 36 (not 3.6) septillion yottawatts. It was only for a few milliseconds though.

You probably wouldn’t have wanted to have been in the same galaxy when it went off. If I’ve done the sums right then, say, the energy yield was 10^47 joules. Here on earth the sun delivers perhaps 5 x 10^7 joules to every square metre at the earth’s surface each day (obviously it all comes in half the day). The black hole event would have delivered all of that in a few milliseconds if you were standing a distance of about 2 x 10^19 metres away. That’s rather smaller than the radius of our galaxy (5 x 10^20 metres) but it’s probably still too close for comfort.